Art theft and vandalism have increased in recent years and sophisticated equipment has been developed to thwart such activities. There are heat sensitive devices, various electric eye systems, sonic devices etc. most of which are costly and difficult to install and maintain. Furthermore, such devices are usually single purpose in that they are useful at times when the area, such as a museum, is closed to the public. Other devices require extensive wiring which must be done unobtrusively so as not to detract from the art presentation.